Seabirds as Sentinels of Ocean Health
Overview
Living Ocean supports an annual study of migrating shearwaters on Lord Howe Island, led by the Institute for Marine & Antarctic Studies, Tasmania.
Shearwaters born on Lord Howe Island migrate to the Sea of Japan and Bering Strait, not making landfall for seven years, after which they return to Lord Howe Island, sometimes to the very same burrow in which they were raised. Their parents had left the island some weeks before they did.
Parent shearwaters forage for their young as far from the island as Sydney, regurgitating large amounts of plastic as well as food for their offspring, resulting in high mortality rates.
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Our aim is to further this critical research into the effects of ingested plastics on marine species.
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In Australia, around 90% of Flesh-footed Shearwater adults and chicks contain plastic (Lavers & Bond 2016).In 2011, one chick was found to have more than 275 pieces of plastic in it’s stomach (equivalent to an average human ingesting 10kg of plastic; Lavers et al. 2014). Recent data (see Publications) indicate this species is one of the world's most heavily contaminated seabirds and chicks that ingest large amounts of plastic have poor body condition and likely suffer reduced juvenile survival. Not surprisingly, Flesh-footed Shearwater populations on Lord Howe Island and in New Zealand have declined significantly over the past few decades.
Pollution of the environment with plastic debris is a significant and rapidly expanding threat to biodiversity due to its abundance, durability, and persistence. Current knowledge of the negative effects of debris on wildlife is largely based on consequences that are readily observed, such as entanglement or starvation. Many interactions with debris, however, result in less visible and poorly documented sublethal effects, and as a consequence, the true impact of plastic is underestimated.
We investigated the sublethal effects of ingested plastic in Flesh-footed Shearwaters (Ardenna carneipes) using blood chemistry parameters as a measure of bird health. The presence of plastic had a significant negative effect on bird morphometrics and blood calcium levels and a positive relationship with the concentration of uric acid, cholesterol, and amylase. That we found blood chemistry parameters being related to plastic pollution is one of the few examples to date of the sublethal effects of marine debris and highlights that superficially healthy individuals may still experience the negative consequences of ingesting plastic debris. Moving beyond crude measures, such as reduced body mass, to physiological parameters will provide much needed insight into the nuanced and less visible effects of plastic.
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Financial support
On-site volunteer support on Lord Howe Island:
Collecting dead and dying juvenile shearwaters
Capturing healthy birds at night for gut plastic assessment, blood sampling, banding and release
Participating in lab work and cooking for exhausted scientists
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Our financial support for blood analysis and support on-site enabled publication by Dr Jennifer Lavers and team of the world’s first scientific paper on the health effects of plastic ingestion on any animal.
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Institute for Marine & Antarctic Studies, University of Tasmania
Adrift Lab
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Dr Jennifer Lavers, IMAS
Dr Alex Bond, Natural History Museum, London
